Lawmakers representing New York have introduced a bill that would permit the head of homeland security to declare no-fly zones around certain nuclear power plants, but the Nuclear Regulatory Commission sees little need for such a measure.

In a post-Sept. 11 world nuclear power reactors are seen as potential targets for terrorist attacks that could have disastrous consequences should radioactive material be released into the environment. Just 35 miles north of Manhattan, the Indian Point power facility seems to embody this concern.

As the owners of the Indian Point reactors seek renewed licenses to operate for the next three decades, New York's attorney general filed a legal brief supporting demands that federal officials in making their decision consider terrorism risks and the feasibility of evacuating the surrounding area.

Westchester County officials in New York have appealed the Nuclear Regulatory Commission's refusal to alter criteria considered in relicensing power plants.

In the meantime, Democratic New York Reps. Nita Lowey, Eliot Engel, and Maurice Hinchey have sponsored a bill that could keep planes away from any nuclear power plant within 50 miles of an urban area where more than 15 million people live.

The bill would allow but not require the homeland security secretary to designate no-fly zones around nuclear plants in those regions. It does not call for a specific security circumference.

"Al-Qaeda has publicly asserted that they have considered targeting nuclear facilities, and we don't know what method that would be," said Lowey spokesman Matt Dennis. "That just poses an unacceptable risk."

Dennis noted that one of the planes that hit the World Trade Center on Sept. 11, 2001, flew over the Indian Point site.

According to the Sept. 11 commission report, original al-Qaeda plans for the 2001 attacks included a total of 10 planes with nuclear power plants in the set of targets.

The Nuclear Regulatory Commission, however, is not particularly concerned about a scenario in which a plane strikes a reactor. "These are naturally robust facilities that are meant to withstand many types of natural disasters," said spokeswoman Holly Harrington. "Studies have shown that there's a low likelihood that it would penetrate to the extent that it would be a public safety hazard."

Dennis said that argument is less than convincing. "These facilities were not built to withstand that and we can't know for sure," he said.

While there are presently no no-fly zones, the Federal Aviation Administration has issued a notice for pilots "that basically tells them not to linger around nuclear power plants," Harrington said.

If a plane or helicopter were perceived as a threat to a power plant, military jets could be scrambled. "We do have a lot of close communication with NORAD," she said, referring to the North American Aerospace Defense Command.

Given the location of some power plants, a no-fly zone could be "highly disruptive" to air traffic, she added.

The New York lawmakers' legislation has been referred to the House Transportation and Infrastructure Committee. Even if approved in Congress and signed by the president, it seems unlikely to be used by the Homeland Security Department.

"The department has done an extraordinary amount of work with the various entities that regulate nuclear facilities," said agency spokesman Russ Knocke, indicating that the department is satisfied with the current security measures. "We've struck the right the balance in risk management of high consequence sites."

Since 2001, plans to protect commercial nuclear reactors have incorporated expanded threat scenarios with a greater number of terrorists attacking by land or possibly over water. The commission rejected a suggested requirement that private reactor security forces be prepared to defend against armor piercing ammunition and rocket-propelled grenades. The guidelines do not require facilities to prepare for an air attack.

In April, the Nuclear Regulatory Commission proposed a rule that companies apply to certify new nuclear reactor designs assess what the impact of a commercial airplane striking the structure would be.

At research reactors, where there is often highly enriched uranium that could be weapons usable, federal official have issued rules requiring additional fingerprinting and background checks of those with access to the facilities.

Regarding threats posed by aircraft, it is "important to not lose sight of the effort that's been made to harden our aviation sector since 9/11," Knocke said. "There are extraordinary layers of security in the aviation sector that have been put in place."